Being able to detect differences in signals is of great interest for the skilled addressee. In the case of audio/video signals, differences may occur due to various reasons.
For instance, an audio signal may become desynchronized with a corresponding video signal during the course of a transmission of the audio/video signal. Such phenomenon is known by the skilled addressee as lip sync. Detecting lip sync may be of great interest tor multiple system operators (MSG) that are looking for example to improve the quality of their channels and to avoid a phenomenon unacceptable at a certain degree for the end user.
Unfortunately, many prior art references for detecting lip sync disclose techniques that are either cumbersome to implement or require excessive processing resources.
Of interest though is PCT application WO 2003/088930 which discloses extracting features of audio and video signal content to provide reliable identification of the signals. In this international application a plurality of intermediate values are extracted. Those intermediate values represent one or more measures of dissimilarities between first and second values. Signatures are then generated by applying a hashing function on those intermediates values.
Unfortunately, the processing associated with such signature generation requires extensive processing capabilities which may not be acceptable in the case of certain applications wherein fast processing and limited processing capabilities are required.
There is therefore a need for a method and apparatus that will overcome at least one of the above-identified drawbacks.
Features of the invention will be apparent from review of the disclosure, drawings and description of the invention below.